Lake weed control is a big topic here in Texas, where we have more lakes than most people could imagine. Exotic aquatic weeds have taken control of some of our reservoirs, and threaten many others, and the same situation is occurring throughout the Southern United States.

Most of these weeds, like hydrilla, giant salvinia, and the deceivingly attractive water hyacinth plant, come to us from exotic locations where natural predators, weather conditions, fertility, and other natural phenomenon kept them under control, but here, they have no such predators, and no controls other than the man made, mechanical control measures, and aquatic herbicides.

Lake and pond weed predators

The importation of natural predators to take care of the problem has met with much resistance, and in some cases, justifiably so, as they seem to destroy much more than just the plants they were brought here to atack. Some even become problems themselves.

All the man made aquatic herbicides, lake weed killers, and biological controls put together can not undo all that could have been stopped to begin with. Once again, the best form of lake weed control, is lake weed prevention.

How to control lake weeds

1. To control lake weeds, stop them from getting a start in your body of water by making sure that none are introduced. Make sure all boats, boat trailers, and sport fishing supplies are cleaned between lakes. Pay special attention to boat propellers, live wells, and anything that went into, or near the water. Fishing tackle needs the same attention, since even a small sprig can start a lake weed fiasco.Other preventive measures include:
2. Raising the water level of the lake or pond, which allows less sunlight to get to the bottom, where most of these weeds get their start.
3. Dredging the edge of the lake or pond, to increase the depth for the same reason.
4. Encouraging the growth of planktonic algae in low fertility ponds by raising the fertility, also keeps light from the bottom. Note: Before doing this, you should check the sechi depth, that is the depth that an 8′ black and white disc can no longer be seen when inserted into the water. If it disappears before the 18 inch mark, there is enough fertility, and if it disappears at a depth lower than 24 inches, it could stand to be fertilized. Checking the pH would also be a good idea before hand, to make sure that the fertilizer will be effective.
5. In the event that the fertility level is too high, you probably suffer from some type of fertilizer runoff into your pond or lake, and may need to install a vegetative buffer, lower the amount of fertilizer used to fertilize lawns and pastures, or some other method to stop the problem. Keeping the pond or lake at a proper level of fertility is one of the best ways to practice lake weed control, and it is also the best method to grow a large, healthy fish population.